Piston



May 2, 1933. w P K 1,906,765

PISTON Filed Nov. 19, 1950 2 Sheets-Sheet l \NVENTOR i/r11 h. IOU/P1017)? May 2, 1933. 4 c. w. PURKEY PISTON Filed Nov. 19, 1930 2 Sheets-Sheet 2 I &9 u

INVENTOR CAI/P11 M Pumrrr BY Patnted Maya, 3 p a V iv a 1,906,765

' s, a rURK EY, or. DETROIT, mrcnrean if Application med November 19, 1930) Serial No..496,671..

" This invention relates to pistons, and parwith said head, just below the latter, is a 7 l ticularly topistons carrying rollers for enpalr of wrist pinbearings 3, suitably spaced .gagelnent with a cylinder wherein the piston apartat opposite sides of the longitudinal reciprocates; I I r "axis of thepiston, and substantially flush at -"-An object of the invention is to reducethe their outer ends with peripheral face of said 55 weight of a piston and minimize the friction head. A suitable bushing/l may be inserted. incident to its use, by replacing the usual 111 each bearii' g,,as is-common' practice. skirt member ofthe piston by a pair of spaced Integral with and downwardly extending "brackets'projectingfrom fthe underface of from. the under face of the head is a pair the head, jointly-mounting a plurality of of brackets 5, which: are further preferably cylinder-engaging rollers parallel to the integral with the innerends of the bearings wrist pin axis of-thepiston, and at: opposite 3 and thus reinforced byjthe latter. Said sides'of-its'*longitudinalaxis. brackets are relatively thin in the direction -Anotl1er-object-is to utilize the wrist pin of the axis of said bearings, while extending bearings to reinforce the connection between transversely toisaid axis substantially a o said brackets'and the piston head. theunder face of the pistonhead.

A further object'is to employ two pairs Betweenthe brackets 5'are mounted two of the described rollers, spacing the. rollers of pairs of rollers 6, each gradually reduced each pair longitudinally ot the piston and from its center'to its ends to substantially the longitudinal axis of the piston.- V 'Each of said rollers is journaled on a pin 7 Still another object is to associate with terminallymounted in slots 8 in said brack said rollers an adjustment meansto initially ets, said slots beingelongated slightly transestablish a proper working relation between Verselyto said pins. Thussaid pins with rollthe rollers in a cylinder wall 'andfto permit ers journaled thereonare afforded a slight compensation forwear of said rollers. v play to and fromthe longitudinal axis of the g These and various other objects. the inven piston. The'bracketsfi have an extent longition attains by the construction'hereinafter tudinally of the piston substantially equal described," and illustrated in the accompanyto that. of a piston skirt in present practice, ing drawings, wherein: f 3 whereby it is made possibleto" space the roll- Fig. 1 is a view in side elevation of the ers 6 of each pair longitudinally of the piston, improved piston; J l I I the upper roller ofeach pair being between Fig. 2 is another side elevati'onal view, par-, the head and wrist pin axis, and the lower 3 tially in section on the line 22of Fig.' 1. rollers beingconsiderably below said axis. Fig. 3 is acrosssectional view of thep1ston- The outer end portions of each pin 7 .have taken on the line 3 3, of Fig. 1. r .7 a lateral face thereof planed for engagement "Fig. 4 is a bottomview of thepiston, I by the .end of a set screw Q'threaded in a lug 'Fig. 5 is a view in side elevation of an 10 integrally outstanding from the adjacent alternative form of the invention. bracket 5, said set screws being adapted to' 0 7 Fig.6 is a bottom view of the same'partly shi'ftsaid pins 'from the longitudinal axis of in s'ectio'nQ" 1 the pist'on to establish proper engagement of Fig. 7 is a vertical sectional, view taken the rollers 6 wit-h the Wall of a cylinder in upon the line'77 of- Fig. 6, which the piston reciprocates. 1 Also, said 5 Fig: 8isja vertical section taken upon the set screws permitsuch adjustment of theroll- 95 line 88io fFig. 6. y I ers as may at times be requisite to compen- 1 Referring now more particularly to these satefor wear. Y views and describing first the construction Describingjn the alternative construcshown inFigs'lto 4, inclusive; the refertion illustrated by Figs.'5 to 8,inclusive', a

r 'ence character .1 designates a piston head havhollow cylindricalpiston head 11, having the m0 ing usualring grooves 21- Formed integrally usualring grooves, isreinforcedfbya :dia-

positioning said'pairs at opposite sides of .conform to the 'peripheral'arc of thehead. I

metrical rib 12. Integrally carried by said rib just below the head is a pair of wrist pin bearings 13, suitably spaced longitudinally of said rib to accommodate a connecting rod therebetween.

Formed integrally with the inner ends of the bearings 13, at one side thereof, is a pair of bracket arms 14 terminally jointly mounting a pin 15 parallel to the axis of said bearings, and from the other side of the latter, at their inner ends, a pair of double bracket arms 16 integrally project, mounting a pair of pins 17 parallel to the pin 15 and spaced longitudinally of the piston. The pins 15 and 17 journal rollers 18 fitted between the arms 14 and between the arms 16, tangential- 1y to the extended cylindrical surface of the head 11, and preferably cored out to reduce their weight. The pins 17 are suitably fixed in the brackets 16 as by rivets 19. r

The pin 15 has its end portions laterally planed, as indicated at 20, and these portions are engaged by acutely beveled ends of wedge members 21 set into vertical bores 22 of the arms 14, the said members being urged upwardly by coiled springs 23. The latter, at their lower ends, seat upon depending L- shaped extensions 2 1 of the arms 1 1. Thus the wedge members'Ql, under upward urge of the springs 23, exert a constant out-ward eil'ort upon the pin 15, to maintain proper contact of the roller 18 with a cylinder wall not shown) and the openings of the arms 14 receiving the pin 15 are slightly elongated transversely of said pin, to ail ord'the latter a slight play for taking up wear.

Inthe use of said piston, in either of ts forms, engagement of the rollers 6 or 18 with a cylinder wall (not shown) prevents any oscillation of the piston about its wrist pin axis, thereby avoiding resultant slap and Said rollers, furthei leakage past the head. 7 more, since they may turn freely as the plston reciprocates, greatly reduce the friction between the piston and the cylinder wall as compared to the cylindrical skirts now commonly employed. i

A further advantage of the described construction is the reduction of weight achieved by the substitution of bracket members and rollers for an ordinary piston skirt.

A still further advantage lies in the possibility of employing a light metal, as aluminum, to form the entire piston, without undue resulting diametrical thermal expansion.

The last described form of the invention so locates the two adjacent rollers thereof as to engage the cylinder wall primarilyduring the power stroke of the piston, the single roller engaging said wall during the return stroke. Thus, the invention in this form takes into consideration the fact that the lateral thrust during the power stroke'considerably exceeds the lateral thrust incident to the compression and scavenging strokes.

Elimination of one of the rollers in the last described construction directly reduces weight and expense, and further indirectly reduces weight by reduction in size of the roller-mounting brackets \Vhile it is apparent that the illustrated embodiments of my invention are well calculated to adequately fulfill the objects and ad vantages primarily stated, it is to be understood that the invention is susceptible to vanation, modification and change within the spirit and scope of the subjoined claims.

What I claim is l. piston comprising a cylindrical head, a pair of spaced brackets projecting from the under face of the head, one at each side of the long tudinal axis of the head, a pair of rollers JOUIIlllQCl upon and between .said brackets at opposite sides of said axis, and positioned to roll upon the cylinder in which said piston operates, and a pair of wrist pin bearings integrally connecting said brackets to said head, and outwardly extending from said brackets, said bearings establishing an axis parallel to that of said rollers.

2. A piston comprising a cylindrical head, a support projecting from the under face of said head, a pair of wrist-pin bearings spaced at opposite sides of the piston axis and integrally connecting said head and support, and two pairs of rollers journaled in said support each parallel to the wrist pin axis and positioned to roll upon the cylinder in. which said piston operates, the rollers of each pair being diametrically opposed, the axes of said pairs being at opposite sides of the transverse plane of the piston determined by the axis of the wrist pin bearings.

3. A piston comprising a head, a pair of wrist pin bearings carried by and below said head, bracket members projecting from said bearings, paired at opposite sides thereof, a pair of rollers carried by one pair of said bracket members having their axes aligned longitudinally of the piston, and a single roller carried by the other pair of bracket members, all of said rollers having their axes substantially parallel.

41.. A piston comprising a c lindrical head,

asupporting structure carried by said head therebeneath, a pair of rollers journaled in said supporting structure, and positioned to roll upon the cylinder in which said piston operates and at one side of the piston axis, and a single roller journaled in said supporting structure, tangentially to said cylinder, at the other side of said axis.

5. A piston comprising a cylindrical head, a supporting structure carried by said head therebeneath, a roller journaled in said structure, and positioned to roll upon the cylinder in which said piston operates, and means carried by'said structure automatically compensating for wear of said roller. I

6. A'piston comprisin g acylindrrcal head,

a supporting structure carried by said head pensate for wear. a

therebeneath, a roller journaled in said structure, and positioned to roll upon'the cylinder 1. in which said piston operates,-and means re- Q siliently urging said roller outwardly to coma a 7. A piston comprising a cylindrical head, a supporting structure carried by said head therebeneath, a pin mounted in said supporting structure, a roller journaled on said pin, and positioned to roll upon'the cylinder in which said piston operates, a pair of wedge piston and positioned to roll upon the c linmembers slidable in said supporting structure substantially longitudinally'of the cylinder and engagingthe ends of said pin, and means for exerting pressure'on said wedge members, whereby said pin is deflected outrwardly to compensate for wear of said roller. A v

8. A piston comprising'a' cylindrical head, a roller-carrying structure rigidly projecting from the under face of said head, a pair of rollers ournaled in said structure at opposite sides of the longitudinal axis of the, piston and positioned to roll Jupon the-cylinder in 'WlllCll said piston operates, a pair of spaced wrist-pin bearings formed integralwith. said structure and establishing an axis parallel to those of said rollers, and means for-individually adjusting saidrollers away fromeach H other. H a v 9. A'piston comprising a cylindrical head, a roller-carrying structure rigidly projecting from the under face of said head, a pair I of rollers journaled in said structure at opposite sides of the longitudinal axis of the der in which said piston operates, a pair of spaced wrist-pin bearings formed integral with said structure and establishing an axis parallel to those of said rollers, a pin journaling each of said rollers and terminallymounted in vsaid structure, and means upon said structure engaging the ends of each pin for adjusting said rollers together with their pins away-from each other.

10. A piston comprising a cylindrical head,

a roller-carryingstructure rigidly projecting from the under face ofsaid head, a pair of rollers journaled in said structure at opposite sides of the longitudinal axis of the piston and positioned to roll upon thercylinder in which said piston operates,a pair of spaced wrist-pin bearings formed integral with said structure and establishing an axis parallel to those of said rollers, a pin journaling each of said rollers, and terminally'mounted in said structure, slugs outwardly projecting V I from said structure, and set'screws threaded in said lugs and bearing on the ends of said pins to ad ustsaid pins and rollers away from each other.

In testimony whereof I sign this. specifica- CARL W. PURKEY;

tion. 

